Optimization of a novel programmable data-flow crypto processor using NSGA-II algorithm.

The optimization of a novel programmable data-flow crypto processor dedicated to security applications is considered. An architecture based on assigning basic functional units to four synchronous regions was proposed in a previous work. In this paper, the problem of selecting the number of synchronous regions and the distribution of functional units among these regions is formulated as a combinatorial multi-objective optimization problem. The objective functions are chosen as: the implementation area, the execution delay, and the consumed energy when running the well-known AES algorithm. To solve this problem, a modified version of the Genetic Algorithm - known as NSGA-II - linked to a component database and a processor emulator, has been invoked. It is found that the performance improvement introduced by operating the processor regions at different clocks is offset by the necessary delay introduced by wrappers needed to communicate between the asynchronous regions. With a two clock-periods delay, the minimum processor delay of the asynchronous case is 311% of the delay obtained in the synchronous case, and the minimum consumed energy is 308% more in the asynchronous design when compared to its synchronous counterpart. This research also identifies the Instruction Region as the main design bottleneck. For the synchronous case, the Pareto front contains solutions with 4 regions that minimize delay and solutions with 7 regions that minimize area or energy. A minimum-delay design is selected for hardware implementation, and the FPGA version of the optimized processor is tested and correct operation is verified for AES and RC6 encryption/decryption algorithms.

Mid-term results of concomitant epiphyseal fixation and trochanteric osteotomy for severe chronic slipped capital femoral epiphysis.

The management of severe forms of slipped capital femoral epiphysis (SCFE) has been the subject of intense debate in the literature, and controversy remains as to whether the proximal femoral epiphysis should be realigned by intracapsular or extracapsular osteotomies or just fixated in situ. The aim of this study is to evaluate the late results of treatment of severe unreduced slipped capital femoral epiphyses by combined epiphyseal stabilisation in situ using a single cancellous screw and biplane corrective trochanteric osteotomy. Eighteen hips with severe chronic slipped capital femoral epiphysis before physeal closure were treated by combined epiphyseal fixation in situ using a single cancellous screw, and biplane corrective osteotomy fixed by an angled blade plate. The average follow-up period was 8 years. All patients achieved near-normal hip flexion, internal rotation and abduction, and most were able to bear weight in the early postoperative period. A satisfactory correction of the head-shaft angle was obtained post-operatively on both antero-posterior and frog leg lateral radiographs. There was no instance of chondrolysis, avascular necrosis or early osteoarthrosis. This procedure appears to offer a workable solution to the problem posed by the severely slipped capital femoral epiphysis.

Functional outcome of four-corner arthrodesis for treatment of grade IV scaphoid non-union.

Functional limitations and pain are end results of scaphoid nonunion with progressive carpal collapse and radiocarpal arthritis. The aim of this study was to assess the functional outcome of four-corner arthrodesis with scaphoidectomy for the treatment of grade IV scaphoid nonunion with Scaphoid Nonunion Advanced Collapse (SNAC) stages II and III. Ten patients with symptomatic grade IV non union of the scaphoid and a mean duration of non unions of 12.1 +/- 2.81 months were treated using the four-corner arthrodesis technique. A dorsal midline longitudinal approach centered over the third metacarpal-capitate-lunate-radius axis, excision of the scaphoid, neutral alignment of the remaining carpal bones, and arthrodesis of the capitate, hamate, lunate, and triquetrum, were performed. Kirschner wires were used to secure the arthrodesis in all cases. A below-elbow thumb spica cast was applied for 3 months. Follow up period ranged from 8 to 24 months, with a mean of 16 +/- 4.7 months. All patients were assessed both functionally for pain, range of motion and grip strength, and radiographically for evidence of fusion and carpal alignment. Good results were achieved in 7 patients (70%) according to the modified Mayo Wrist Scoring Chart. There were no intraoperative complications. Postoperatively, one patient suffered superficial wound infection One patient showed dorsal impingement of the capitate and radius. Also, two patients suffered reflex sympathetic dystrophy. No patients showed deep infection or nonunion. The Four-corner Arthrodesis technique is a motion-sparing, limited arthrodesis that reliably results in pain relief, improved grip strength, and overall patient satisfaction with low associated non union and complication rates.

Reconstruction plate fixation of subtrochanteric femoral fractures in children.

Pediatric subtrochanteric femoral fractures are rare and have received limited attention in the literature Treatment is controversial. Different treatment options are used: skin traction, 90/90 skeletal traction, spica casting, cast bracing, internal fixation and external fixation. The aim of this study is to present our results with internal fixation of subtrochanteric femoral fractures in children using a reconstruction plate. Between 2000 and 2004, eighteen patients with closed subtrochanteric femoral fractures were treated in the Mansoura Emergency Hospital. The average age at the time of injury was 8.2 years (range 5.3 years to 11.5 years). Pathological fractures and fractures associated with neuromuscular diseases were excluded from this study. Eight patients had head injuries and/or multiple injuries. In all cases a single 4.5 mm contoured reconstruction plate was used and a 6.5 mm cancellous screw was inserted through the plate into the femoral neck. Average follow-up was 38 months (range, 12 to 47 months). All fractures united with anatomical alignment within an average of 8 weeks (range 6 to 12 weeks). There were no deep infections and no significant limb length discrepancies. At the latest follow-up, no patient had any restriction of activities. Internal fixation with a reconstruction plate appears as a good treatment option for children with subtrochanteric femoral fractures.

Free non-vascularised fibular graft for treatment of post-traumatic bone defects.

Post-traumatic bone defects usually occur from severe high-velocity injuries due to road traffic accidents; they may be difficult to fill. We have managed defects of long bones by the use of free non-vascularised fibular grafts harvested subperiosteally and held by screw fixation of the fibular strut ends to the ends of the bone defect, combined with an external fixator in 8 tibial defects and with a plate and screws in 2 ulnae and 2 humeri. Twelve patients, eleven male and one female, with a mean average age of 25 years (range 12-40), underwent this procedure. Eleven grafts (92%) united at both ends within an average of 4 months (range, 3 to 5 months). The defect lengths averaged 7 cm (range from 6 to 10 cm). The long-term follow-up showed complete 'tibialisation' of the fibula. Non-vascularised fibular graft, compared to microvascular reconstruction and Ilizarov techniques, is a simple procedure that is still valid to bridge bone defects successfully in selected cases.

Proximal row carpectomy: a motion-preserving procedure in the treatment of advanced Kienbock's disease.

Kienbock's disease is an isolated disorder of the lunate bone resulting from vascular compromise to the bone. In stage IV, degenerative changes are present at the midcarpal joint, the radiocarpal joint, or both. The goal of proximal row carpectomy (PRC) is the creation of a new joint between the capitate and the radius. The aim of this prospective study was to evaluate the functional outcome after PRC in late stage Kienbock's disease. The evaluation included assessment of range of motion, grip strength, and pain reduction. Twelve wrists in 12 patients underwent proximal row carpectomy for the treatment of stage IV Kienbock's disease between 2002 and 2005. Objective and subjective function was assessed. The average length of follow-up was 2 years (range, 9 months to 4 years). There was one failure (8.3%) requiring fusion at three years. The eleven wrists that did not fail (91.7%) had an average flexion-extension are of 70 degrees, associated with an average grip strength of 80% of the contralateral side; all patients were very satisfied. The patients rated nine wrists as not painful, two as mildly painful, and one as moderately painful. Radiographs revealed reduced radiocapitate space in five and complete loss of the space in one. With the numbers available, there was no significant association between loss of joint space seen on radiographs and subjective and objective function. Overall, proximal row carpectomy had maintained a satisfactory range of motion, grip strength, and pain relief, and all twelve patients with Kienbock's disease, except one, were satisfied with the results and returned to their previous occupations. Caution should be exercised in performing the procedure in a young, heavy manual working patient.